Army reinforcements were rushed into Thailand's capital as tens of thousands of anti-government demonstrators marched Monday on a key military headquarters demanding that the government dissolve Parliament.Some 100,000 Red Shirt protesters who have been camped out along a boulevard in the old part of Bangkok have given Prime Minister Abhisit Vejjajiva a noon deadline to meet their demand for new elections.A force of more than 50,000 soldiers, police and other security personnel has been mobilized in the capital area, and many were deployed at the 11th Infantry Regiment headquarters where Abhisit has been hunkered down in recent days.With banners waving, thousands of the protesters piled into trucks, rode motorcycles or trudged on foot toward the barbed-wire ringed regimental compound.City authorities feared traffic chaos in areas of the sprawling capital, but in other quarters, traffic was surprisingly light for a normally clogged Monday morning as many office workers stayed home for fear of violence.But the protest, one of the largest staged in recent years, has proved peaceful.At the main demonstration site Sunday, loud pop music and rural delicacies such as spicy papaya salad competed with fiery rhetoric for the attention of the crowd, many of whom had come from provinces in the countryside. The festive tone was aided by hundreds of new arrivals disembarking from boats festooned with red banners on the Chao Phraya River. The protesters, formally grouped as the United Front for Democracy against Dictatorship, have been flexible in their tactics and deadlines, but are demanding Abhisit dissolve Parliament and call new elections, which they believe will restore their political allies to power.They believe Abhisit took office illegitimately with the connivance of the military and other parts of the traditional ruling class who were alarmed by former Prime Minister Thaksin Shinawatra's popularity, particularly among the poor. Thaksin, who became prime minister in 2001 and whose party easily won two elections, was ousted by a 2006 military coup for alleged corruption and abuse of power.Abhisit indicated Sunday that for now, he had no plans to dissolve Parliament.Thaksin spoke to the rally by video link Sunday night, urging the crowd to continue their struggle peacefully, and emphasizing that he considered the so-called "ammart," or elite, the enemy. Thaksin himself is a billionaire businessman who fled Thailand in 2008 ahead of being convicted for a conflict of interest violation and sentenced to two years in jail."The people who caused the problems in the country these days are the ruling elites," declared Thaksin, speaking from an undisclosed location outside of Thailand. "To solve problems related to democracy, equality and justice — the ruling elites won't be able to do that because they don't have the conscience. The people will have to do it."He suggested that if he returned to power, he would redistribute wealth and keep Thailand economically competitive with its neighbors.The protest had been billed as a "million man march," but protest leader Natthawut Saikua said he believed more than a half million people turned up, while estimates from the police and other government agencies ranged from 50,000-150,000.Associated Press reporters said it was one of the biggest turnouts in the past five years of frequent protests, which would put it over the 100,000 mark. The Red Shirts' last major protest in Bangkok last April deteriorated into rioting that left two people dead, more than 120 people injured and buses burned on major thoroughfares before the army quashed the unrest."We are being vigilant. We are still concerned about the third handthat might instigate troubles. But the Red Shirts are adamant aboutkeeping their rally peaceful, and so far they have been peaceful.Everything has been done step by step. Every side is cautious,"government spokesman Panithan Wattanayakorn said Sunday night.Thailandhas been in constant political turmoil since early 2006, whenanti-Thaksin demonstrations began. In 2008, when Thaksin's politicalallies came back to power for a year, his opponents occupied the primeminister's office compound for three months and seized Bangkok's twoairports for a week.